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AssigneeLock Technology, Inc.
InventorsGeorge V. Iaccino, Robert A. Idoni
Estimating the term…
Methods and apparatus for decoding twisting tumbler locks and improvements in such locks to resist such methods and apparatus. To determine depth of cut of bit for a given tumbler, a blade is inserted into key way to position a wirelike probe at tumbler to be decoded. Wirelike probe is advanced upwardly until it engages tit at top of tumbler. Depth of cut of key bit is function of length of tumbler and device can be calibrated to give direct readout of depth of bit cut. Angle of key bit can be measured by hooking a wirelike probe in side gate groove in tumbler and then twisting tumbler until tit engages key plug or shell. Amount of twist permitted is function of angular position required to register tumbler groove with side gate and device can be calibrated to give direct reading of such angle. To defeat depth of cut decoder, twisting tumbler lock wherein tits on tumblers are located at different distances from tops of tumblers is disclosed. Another form of modified twisting tumbler locks that will defeat decoding methods and apparatus herein is tumbler with side gates receiving grooves 180.degree. apart and with no tit.
A method of decoding the depth of bit cut for a key for a twisting tumbler lock of the type which includes a side bar;
Apparatus for decoding the depth of bit cut for a key for a lock of the type including a rotatable key plug having a longitudinally extending keyway therein and a plurality of transversely extending longitudinally spaced holes, each communicable to and from a locking position and from and to an unlocked position wherein the end of said tumbler remote from said keyway is in the plane of the surface of said key plug, said apparatus comprising:
The method of decoding the required angulation of bit for a key for a twisting tumbler lock of the type which includes a side bar;
Apparatus for decoding the angulation of a bit for a key for a lock of the type including a rotatable key plug having a longitudinally extending keyway therein and a plurality of transversely extending longitudinally spaced holes, each communicating with said keyway, and a tumbler in each of said holes movable to and from a locking position and from and to an unlocked position wherein the end of said tumbler remote from said keyway is in the plane of the surface of said key plug, said apparatus comprising:
A cylinder lock comprising a cylinder shell and a key plug rotatably mounted therein, the interface between said shell and said key plug defining a shear plane, a keyway in said key plug, a plurality of cylindrical reciprocally and rotatably mounted tumblers in said key plug reciprocally movable to and from an unlock position in which an and of said tumbler is essentially in said shear plane and from and to a lock position, each of said tumblers having their other ends disposed adjacent said keyway and being chisel shaped, whereby when a key with angulated bite is disposed in said keyway, said tumbler will rotate, said key plug having a plurality of slots, one for each tumbler, adjacent each tumbler, a tit on each tumbler extending into its associated key plug slot for limiting the rotation of said tumbler, at least two of said tumblers having said tits at different distances from said first mentioned end of said tumbler, a side gate in said key plug being laterally movable from a lock position in which said side gate straddles said shear plane to an unlock position in which said side gate is clear of said shear plane, with tumblers normally blocking movement of said side gate to said unlock position, said tumblers being shaped so that upon engagement with a proper bitted key said side is free to move to said unlock position.
Dependencies are inferred from the claim text.